<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>

        /*函数的相互调用  可以无限循环  */
        function a(){
            alert(1)
            b();
        }

        a();

        function b(){
            alert(2)
          //  a();
        }
    </script>
</head>
<body>

</body>
</html>